1. Field of the Invention
The present invention relates generally to medical apparatus and methods. More particularly, the present invention relates to the construction and use of gastric balloons for treating obesity.
Obesity is a serious medical condition and has become a widespread problem in the United States and many other industrialized countries. While many obese patients may be treated by modifications to diet and exercise, a number of morbidly obese patients are resistant to treatment and are candidates for surgical intervention. One surgical approach for treating morbid obesity is referred to as gastric or jejunoileal bypass where a major portion of the gastro-intestinal tract is surgically bypassed. While effective in some patients, gastric bypass procedures can have significant undesirable side affects. Moreover, the initial surgical procedure presents risks associated with open surgery. There are restrictive surgical procedures but they are less effective and still invasive. Consequently, an effective, non-invasive medical treatment with lower risks and minimal side effects is needed for many morbidly obese patients, who cannot tolerate surgical intervention, and most premorbidly obese patients, who have no effective treatment because their condition is not sufficiently severe to qualify them as surgical candidates.
As an alternative to such surgical procedures, the introduction of space-occupying structures into the stomach, often referred to as “gastric balloons,” has been proposed. Such gastric balloons may be introduced through the esophagus and inflated in situ in order to occupy a significant volume within the stomach.
Although found to be effective in some cases, the use of gastric balloons has been compromised by a number of deficiencies. The most serious is a sudden or slow deflation of the gastric balloon that can allow the balloon to pass the pyloric valve and enter the intestines. Such unintentional passage of the deflated balloon into the intestines can cause intestinal obstruction and be life-threatening. Consequently, gastric balloons currently marketed outside the US are generally indicated for use of only up to six months.
The risk of deflation is exacerbated by the fact that the patient may not immediately be aware that the balloon has deflated, delaying the patient from seeing a physician. Thus, it would be desirable to provide approaches to allow a patient to detect leakage or impending leakage. Currently to detect leakage, some practitioners add methylene blue dye to the filling fluid, usually saline, prior to inflation. If the methylene blue leaks into the stomach, a blue color will be present in the patient's excrement. This procedure has a number of deficiencies as evidenced by the continued reports of significant rates of intestinal obstruction and excretion of deflated balloons in clinical practice. Slow and intermittent leaks can release such small amounts of dye that the dye is not detectable in the excrement. Faults on the medical professionals' part include mixing concentrations that makes detection unreliable or simply forgetting to mix in the substance prior to inflating the balloon. On the patients' side, many have difficulties detecting slight changes in the color of the excrement, forget to check diligently, or simply find the task psychologically too unpleasant to perform.
Other problems include infections resulting from bacterial colonization of the gastric balloon and lack of adequate sizing of the balloon prior to deployment in a patient's stomach. Additionally, most gastric balloons have been filled with saline or other liquid, making them heavy and uncomfortable within a patient's stomach. The weight of the balloons can cause them to induce gastric hypertrophy and create gastric erosions, ulcers, lesions and abrasions within the stomach at the points where they naturally rest.
For these reasons, it would be desirable to provide improved gastric balloon structures and methods for their use in treating obese patients. The balloons should be durable and the methods and apparatus will preferably be comfortable to the patient and in particular should avoid settling as a heavy weight in the patient's stomach. The gastric balloons and methods for their use should further prevent passage of an accidentally deflated balloon across the pyloric valve and into the intestines, even when the balloon structure is compromised and the balloon looses inflation medium. It would be further desirable if a deflation or impending deflation of the balloon were detectable to the patient in a rapid and reliable fashion. Such a detection system should alert the patient of failure and allow the patient to seek medical help before the balloon has deflated to a size that could pass the pylorus. The compromised device could be then removed or replaced on a timely basis. Additionally, it would be beneficial if the balloons were resistant to bacterial and other microbial growth, thus lessening the risk of infection upon long-term deployment. Other improvements would include balloons and methods for their deployment which allow for proper sizing the balloon and/or trimming or adjusting the balloon size even after deployment. At least some of these objectives will be met by the inventions described below.
2. Description of the Background Art
Gastric balloons and methods for their use in treating obesity are described in U.S. Pat. Nos. 6,746,460; 6,736,793; 6,733,512; 6,656,194; 6,579,301; 6,454,785; 5,993,473; 5,259,399; 5,234,454; 5,084,061; 4,908,011; 4,899,747; 4,739,758; 4,723,893; 4,694,827; 4,648,383; 4,607,618; 4,501,264; 4,485,805; 4,416,267; 4,246,893; 4,133,315; 3,055,371; and 3,046,988 and in the following publications: U.S. 2004/0186503; U.S. 2004/0186502; U.S. 2004/0106899; U.S. 2004/0059289; U.S. 2003/0171768; U.S. 2002/0055757; WO 03/095015; WO88/00027; WO87/00034; WO83/02888; EP 0103481; EP0246999; GB2090747; and GB2139902.